unittests: Adds x87 integer indefinite test

Tests 16-bit, 32-bit, and 64-bit integer conversions

unittests/ASM/FEX_bugs/x87_integer_indefinite.asm

@@ -0,0 +1,87 @@
+%ifdef CONFIG
+{
+  "RegData": {
+    "RAX": "0x8000",
+    "RBX": "0x8000",
+    "RCX": "0x80000000",
+    "RDX": "0x80000000",
+    "RSI": "0x8000000000000000",
+    "RDI": "0x8000000000000000"
+  }
+}
+%endif
+
+; FEX-Emu had a bug where x87 float to integer conversions weren't converting to the correct "integer indefinite" value for 16-bit conversions.
+; Test 16-bit, 32-bit, and 64-bit to ensure correct "integer indefinite" results for all.
+; The definition for "integer indefinite" is the smallest negative integer that can be represented.
+; This is regardless of the input value being positive or negative.
+fninit
+
+; 16-bit
+fld qword [rel .double_larger_than_int16]
+fistp word [rel .data_res_pos_16]
+
+fld qword [rel .double_smaller_than_int16]
+fistp word [rel .data_res_neg_16]
+
+; 32-bit
+fld qword [rel .double_larger_than_int32]
+fistp dword [rel .data_res_pos_32]
+
+fld qword [rel .double_smaller_than_int32]
+fistp dword [rel .data_res_neg_32]
+
+; 64-bit
+fld qword [rel .double_larger_than_int64]
+fistp qword [rel .data_res_pos_64]
+
+fld qword [rel .double_smaller_than_int64]
+fistp qword [rel .data_res_neg_64]
+
+; Load the results
+movzx rax, word [rel .data_res_pos_16]
+movzx rbx, word [rel .data_res_neg_16]
+
+mov ecx, dword [rel .data_res_pos_32]
+mov edx, dword [rel .data_res_neg_32]
+
+mov rsi, qword [rel .data_res_pos_64]
+mov rdi, qword [rel .data_res_neg_64]
+
+hlt
+
+; One-integer larger than what int16_t can hold
+.double_larger_than_int16:
+dq 32768.0
+; One-integer smaller than what int16_t can hold
+.double_smaller_than_int16:
+dq -32769.0
+
+; One-integer larger than what int32_t can hold
+.double_larger_than_int32:
+dq 2147483648.0
+; One-integer smaller than what int32_t can hold
+.double_smaller_than_int32:
+dq -2147483649.0
+
+; One-integer larger than what int64_t can hold
+.double_larger_than_int64:
+dq 9223372036854775808.0
+; One-integer smaller than what int64_t can hold
+.double_smaller_than_int64:
+dq -9223372036854775809.0
+
+.data_res_pos_16:
+dw -1
+.data_res_neg_16:
+dw -1
+
+.data_res_pos_32:
+dd -1
+.data_res_neg_32:
+dd -1
+
+.data_res_pos_64:
+dq -1
+.data_res_neg_64:
+dq -1