UnitTestFrameworkPkg: Expand host-based exception handling and gcov

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4683

Update MSFT CC_FLAGS for host-based unit tests to use /EHs
instead of /EHsc to support building C functions with SEH
(Structured Exception Handling) enabled.  This is required to
build UnitTestDebugAssertLibHost.inf.

Update GCC CC_FLAGS for host-based unit tests to use -fexceptions
to support catching exceptions.

Update GoogleTestLib.h to include Throws() APIs that enable
unit tests to use EXPECT_THAT() to check for expected ASSERT()
conditions for a specific ASSERT() expression.

Update GCC CC_FLAGS to add --coverage for host-based builds
for all GCC tool chains.

Cc: Michael Kubacki <mikuback@linux.microsoft.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Michael Kubacki <michael.kubacki@microsoft.com>

UnitTestFrameworkPkg/UnitTestFrameworkPkg.ci.yaml

@@ -102,6 +102,8 @@
             "cobertura",
             "DHAVE", # build flag for cmocka in the INF
             "gtest", # file name in GoogleTestLib.inf
+            "defiapi",      # build flag for gtest
+            "fexceptions",  # build flag for gtest
             "corthon",      # Contact GitHub account in Readme
             "mdkinney",     # Contact GitHub account in Readme
             "spbrogan"      # Contact GitHub account in Readme