Fix RNTester hermesc build issue on iOS (#51989)

Summary:
I am not sure exactly why, but I've been getting this error when running RNTester on iOS, when it tries to build hermesc from source. We're clearing the env using `env -i` which seems to cause the issue. If I add PATH to the env we set then it builds fine.

```
++ hermesc_dir_path=/Users/janicduplessis/Developer/react-native/packages/rn-tester/Pods/hermes-engine/build_host_hermesc
++ shift
++ jsi_path=/Users/janicduplessis/Developer/react-native/packages/rn-tester/Pods/../../react-native/ReactCommon/jsi
+++ xcode-select -p
++ SDKROOT=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
++ env -i SDKROOT=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk /opt/homebrew/bin/cmake -S /Users/janicduplessis/Developer/react-native/packages/rn-tester/Pods/hermes-engine -B /Users/janicduplessis/Developer/react-native/packages/rn-tester/Pods/hermes-engine/build_host_hermesc -DJSI_DIR=/Users/janicduplessis/Developer/react-native/packages/rn-tester/Pods/../../react-native/ReactCommon/jsi
CMake Error: CMake was unable to find a build program corresponding to "Unix Makefiles".  CMAKE_MAKE_PROGRAM is not set.  You probably need to select a different build tool.
CMake Error: CMAKE_C_COMPILER not set, after EnableLanguage
CMake Error: CMAKE_CXX_COMPILER not set, after EnableLanguage
-- Configuring incomplete, errors occurred!
Command PhaseScriptExecution failed with a nonzero exit code
```

## Changelog:

[INTERNAL] [FIXED] - Fix RNTester hermesc build issue on iOS

Pull Request resolved: #51989

Test Plan: Build RN tester locally

Reviewed By: cortinico

Differential Revision: D76606335

Pulled By: cipolleschi

fbshipit-source-id: f442b77aefb3afacd6d9fb1f3d515b8d63c526ba

Author: janicduplessis

packages/react-native/sdks/hermes-engine/utils/build-hermesc-xcode.sh

@@ -10,9 +10,17 @@ hermesc_dir_path="$1"; shift
 jsi_path="$1"
 
 # This script is supposed to be executed from Xcode "run script" phase.
-# Xcode sets up its build environment based on the build target (iphone, iphonesimulator, macodsx).
+# Xcode sets up its build environment based on the build target (iphone, iphonesimulator, macosx).
 # We want to make sure that hermesc is built for mac.
 # So we clean the environment with env -i, and explicitly set SDKROOT to macosx
 SDKROOT=$(xcode-select -p)/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
-env -i SDKROOT="$SDKROOT" "$CMAKE_BINARY" -S "${PODS_ROOT}/hermes-engine" -B "$hermesc_dir_path" -DJSI_DIR="$jsi_path"
-env -i SDKROOT="$SDKROOT" "$CMAKE_BINARY" --build "$hermesc_dir_path" --target hermesc -j "$(sysctl -n hw.ncpu)"
+
+env -i \
+  PATH="$PATH" \
+  SDKROOT="$SDKROOT" \
+  "$CMAKE_BINARY" -S "${PODS_ROOT}/hermes-engine" -B "$hermesc_dir_path" -DJSI_DIR="$jsi_path"
+
+env -i \
+  PATH="$PATH" \
+  SDKROOT="$SDKROOT" \
+  "$CMAKE_BINARY" --build "$hermesc_dir_path" --target hermesc -j "$(sysctl -n hw.ncpu)"