Fix compiler ids regex matching

[nmnobre]

Fixes #2978.

Summary

To understand what I'm trying to fix here, first note:

amrex/Tools/CMake/AMReXFlagsTargets.cmake

Lines 71 to 95 in b3f6738

	target_compile_options( Flags_CXX
	INTERFACE
	$<${_cxx_gnu_dbg}:-O0 -ggdb -Wall -Wno-sign-compare -Wno-unused-but-set-variable -Werror=return-type>
	# $<$<VERSION_GREATER:$<CXX_COMPILER_VERSION>,5.0>:-Wnull-dereference>
	$<${_cxx_gnu_rwdbg}:-Werror=return-type>
	$<${_cxx_gnu_rel}:-Werror=return-type>
	$<${_cxx_intel_dbg}:-O0 -traceback -Wcheck>
	$<${_cxx_intel_rwdbg}:-ip -qopt-report=5 -qopt-report-phase=vec>
	$<${_cxx_intel_rel}:-ip -qopt-report=5 -qopt-report-phase=vec>
	$<${_cxx_pgi_dbg}:-O0 -Mbounds>
	$<${_cxx_pgi_rwdbg}:-gopt -fast>
	$<${_cxx_pgi_rel}:-gopt -fast>
	$<${_cxx_cray_dbg}:-O0>
	$<${_cxx_cray_rwdbg}:>
	$<${_cxx_cray_rel}:>
	$<${_cxx_clang_dbg}:-O0 -Wall -Wextra -Wno-sign-compare -Wno-unused-parameter -Wno-unused-variable>
	$<${_cxx_clang_rwdbg}:>
	$<${_cxx_clang_rel}:>
	$<${_cxx_appleclang_dbg}:-O0 -Wall -Wextra -Wno-sign-compare -Wno-unused-parameter -Wno-unused-variable>
	$<${_cxx_appleclang_rwdbg}:>
	$<${_cxx_appleclang_rel}:>
	$<${_cxx_intelllvm_dbg}:-O0 -Wall -Wextra -Wno-sign-compare -Wno-unused-parameter -Wno-unused-variable>
	$<${_cxx_intelllvm_rwdbg}:-gline-tables-only -fdebug-info-for-profiling> # recommended by Intel VTune
	$<${_cxx_intelllvm_rel}:>
	)

Then, with Intel's classic compilers, configure AMReX with -DCMAKE_BUILD_TYPE=Debug and note the C++ flags listed under "AMReX configuration summary", before and after the changes suggested here. The gist is Intel as a compiler id was matching IntelLLVM (and Clang was also matching AppleClang though the flags in that case are the same, so it's harder to tell).
EDIT: this actually only affects what's printed in the summary, the flags that are actually used are already correct!

The proposed changes:

• fix a bug or incorrect behavior in AMReX
• add new capabilities to AMReX
• changes answers in the test suite to more than roundoff level
• are likely to significantly affect the results of downstream AMReX users
• include documentation in the code and/or rst files, if appropriate