[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/underscoresInNumericLiterals/illegalUnderscores.fir.kt

@@ -0,0 +1,17 @@
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+
+fun foo() {
+    1_
+    0x_f
+    0X_f
+    0b_1
+    0B_1
+    1.0_
+    1_.1
+    1.0_e1
+    1.0E_1
+    0Xe_
+    1.1_e-1_23
+    1.0e+_0
+    1.0e-_0
+}

compiler/testData/diagnostics/tests/underscoresInNumericLiterals/noUnderscores.fir.kt

@@ -0,0 +1,9 @@
+// !LANGUAGE: -UnderscoresInNumericLiterals
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+
+fun foo() {
+    100_1
+    3_.1
+    2___4
+    123_
+}