[FR]: Allow EXPECT_NONFATAL_FAILURE and EXPECT_FATAL_FAILURE to expect more than one failure

### Does the feature exist in the most recent commit?

No

### Why do we need this feature?

GoogleTest and GoogleMock allow multiple failures to be thrown. By using, for example, `EXPECT_THAT...`.

GoogleTest also allows it to be used as an foundation/framework for other test frameworks. I so happen to be doing exactly that. And I have multiple tests that would have multiple EXPECT calls to fail in one test.

However, EXPECT_NONFATAL_FAILURE and EXPECT_FATAL_FAILURE only allow for one error to be thrown.

### Describe the proposal.

Either extend/augment the function-like-macro for EXPECT_NONFATAL_FAILURE and EXPECT_FATAL_FAILURE to accept an integer for the amount of failures _or_ allow the substr to be of a list/initializerlist/vector type to expect multiple (different?) substrings.

_or_

Add a second pair of EXPECT_NONFATAL_FAILURE and EXPECT_FATAL_FAILURE, for example, EXPECT_MULTIPLE_NONFATAL_FAILURE and its brother EXPECT_MULTIPLE_FATAL_FAILURE taking a list of substr to match against.

### Is the feature specific to an operating system, compiler, or build system version?

No

Start by locating the existing EXPECT_NONFATAL_FAILURE and EXPECT_FATAL_FAILURE macro implementations and their tests. Compare how they capture and match failures, then clarify whether the intended change is a failure count, multiple substrings, or new macros. Done means a decided API supports multiple expected failures with corresponding coverage.

Written by the indexing model from the issue text.