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/Include/Library/GoogleTestLib.h

@@ -13,6 +13,26 @@
 #include <gmock/gmock.h>
 #include <cstring>
 
+using ::testing::Throws;
+using ::testing::ThrowsMessage;
+using ::testing::HasSubstr;
+
+//
+// Extended macros for testing exceptions with a specific description string
+// in the exception message.  Typically used to check that the expression
+// that generates an ASSERT() matches the expected expression.
+//
+#define EXPECT_THROW_MESSAGE(statement, description)            \
+  EXPECT_THAT (                                                 \
+    []() { statement; },                                        \
+    ThrowsMessage<std::runtime_error>(HasSubstr (description))  \
+    )
+#define ASSERT_THROW_MESSAGE(statement, description)            \
+  ASSERT_THAT (                                                 \
+    []() { statement; },                                        \
+    ThrowsMessage<std::runtime_error>(HasSubstr (description))  \
+    )
+
 extern "C" {
   #include <Uefi.h>
 }