Re-land: [FIRRTL][CAPI] Add more functions for discriminating and querying type

[SpriteOvO]

Re-push #7960, closes #7970.

In #7960, I used memcmp for comparing 2 struct FIRRTLBundleField, this is problematic and may return unexpected results since 2 MlirXXX different opaque pointer structs may be the same content.

bool bundleFieldEqual(const FIRRTLBundleField *lhs,
                      const FIRRTLBundleField *rhs) {
  return mlirIdentifierEqual(lhs->name, rhs->name) &&
         lhs->isFlip == rhs->isFlip && mlirTypeEqual(lhs->type, rhs->type);
}

After replacing it with function bundleFieldEqual above, it should be correct and the crash no longer occurs on Windows, and Valgrind no longer reports Conditional jump or move depends on uninitialised value(s). The uninitialized memory error from Valgrind could be because memcmp accessed struct padding, but I'm confused as to why Windows reports it as 0xc0000409 (STATUS_STACK_BUFFER_OVERRUN). 😶‍🌫️

[seldridge]

SGTM