coverage: Add tests/coverage/loop-break.rs

This is a modified copy of `tests/mir-opt/coverage/instrument_coverage.rs`.

Author: Zalathar

tests/coverage/loop-break.cov-map

@@ -0,0 +1,14 @@
+Function name: loop_break::main
+Raw bytes (31): 0x[01, 01, 01, 01, 05, 05, 01, 03, 01, 00, 0b, 03, 01, 05, 01, 27, 01, 02, 0d, 00, 12, 05, 01, 0a, 00, 0b, 01, 02, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 1
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+Number of file 0 mappings: 5
+- Code(Counter(0)) at (prev + 3, 1) to (start + 0, 11)
+- Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 39)
+    = (c0 + c1)
+- Code(Counter(0)) at (prev + 2, 13) to (start + 0, 18)
+- Code(Counter(1)) at (prev + 1, 10) to (start + 0, 11)
+- Code(Counter(0)) at (prev + 2, 1) to (start + 0, 2)
+

tests/coverage/loop-break.coverage

@@ -0,0 +1,14 @@
+   LL|       |//@ edition: 2021
+   LL|       |
+   LL|      1|fn main() {
+   LL|      1|    loop {
+   LL|      1|        if core::hint::black_box(true) {
+   LL|      1|            break;
+   LL|      0|        }
+   LL|       |    }
+   LL|      1|}
+   LL|       |
+   LL|       |// This test is a lightly-modified version of `tests/mir-opt/coverage/instrument_coverage.rs`.
+   LL|       |// If this test needs to be blessed, then the mir-opt version probably needs to
+   LL|       |// be blessed too!
+

tests/coverage/loop-break.rs

@@ -0,0 +1,13 @@
+//@ edition: 2021
+
+fn main() {
+    loop {
+        if core::hint::black_box(true) {
+            break;
+        }
+    }
+}
+
+// This test is a lightly-modified version of `tests/mir-opt/coverage/instrument_coverage.rs`.
+// If this test needs to be blessed, then the mir-opt version probably needs to
+// be blessed too!