colexecbase: move a single struct to clean up dependencies

This commit moves `colexecbase.BinaryOverloadHelper` into `colexecutils`
package in order to break the dependencies of `colexecproj` and
`colexecprojconst` packages on `colexecbase`. This will speed up the
build a bit.

Release note: None

pkg/sql/colexec/colexecbase/BUILD.bazel

@@ -8,7 +8,6 @@ go_library(
         "distinct.go",
         "fn_op.go",
         "ordinality.go",
-        "overloads_bin_util.go",
         "simple_project.go",
         ":gen-exec",  # keep
     ],

pkg/sql/colexec/colexecproj/BUILD.bazel

@@ -15,7 +15,6 @@ go_library(
         "//pkg/col/typeconv",  # keep
         "//pkg/server/telemetry",  # keep
         "//pkg/sql/colconv",  # keep
-        "//pkg/sql/colexec/colexecbase",  # keep
         "//pkg/sql/colexec/colexeccmp",  # keep
         "//pkg/sql/colexec/colexecutils",  # keep
         "//pkg/sql/colexec/execgen",  # keep
@@ -97,6 +96,7 @@ disallowed_imports_test(
     [
         "//pkg/sql/colexec",
         "//pkg/sql/colexec/colexecagg",
+        "//pkg/sql/colexec/colexecbase",
         "//pkg/sql/colexec/colexechash",
         "//pkg/sql/colexec/colexecjoin",
         "//pkg/sql/colexec/colexecprojconst",