[2020-02] Backport r4-conv-i fixes (#20986)

* [mini] Add missing opcodes for r4 to native int conversions

* [interp] Add handling for conv.i from r4

mono/mini/cpu-arm.md

@@ -227,6 +227,7 @@ rmove: dest:f src1:f len:4
 r4_conv_to_i1: dest:i src1:f len:88
 r4_conv_to_i2: dest:i src1:f len:88
 r4_conv_to_i4: dest:i src1:f len:88
+r4_conv_to_i: dest:i src1:f len:88
 r4_conv_to_u1: dest:i src1:f len:88
 r4_conv_to_u2: dest:i src1:f len:88
 r4_conv_to_u4: dest:i src1:f len:88

mono/mini/cpu-arm64.md

@@ -229,6 +229,7 @@ r4_conv_to_u2: dest:i src1:f len:8
 r4_conv_to_i4: dest:i src1:f len:8
 r4_conv_to_u4: dest:i src1:f len:8
 r4_conv_to_i8: dest:l src1:f len:8
+r4_conv_to_i: dest:l src1:f len:8
 r4_conv_to_u8: dest:l src1:f len:8
 r4_conv_to_r4: dest:f src1:f len:4
 r4_conv_to_r8: dest:f src1:f len:4

mono/mini/interp/transform.c

@@ -4201,6 +4201,13 @@ generate_code (TransformData *td, MonoMethod *method, MonoMethodHeader *header,
 				interp_add_ins (td, MINT_CONV_I8_R8);
 #else
 				interp_add_ins (td, MINT_CONV_I4_R8);
+#endif
+				break;
+			case STACK_TYPE_R4:
+#if SIZEOF_VOID_P == 8
+				interp_add_ins (td, MINT_CONV_I8_R4);
+#else
+				interp_add_ins (td, MINT_CONV_I4_R4);
 #endif
 				break;
 			case STACK_TYPE_I4:

mono/mini/mini-arm.c

@@ -5909,6 +5909,7 @@ mono_arch_output_basic_block (MonoCompile *cfg, MonoBasicBlock *bb)
 			code = emit_r4_to_int (cfg, code, ins->dreg, ins->sreg1, 2, FALSE);
 			break;
 		case OP_RCONV_TO_I4:
+		case OP_RCONV_TO_I:
 			code = emit_r4_to_int (cfg, code, ins->dreg, ins->sreg1, 4, TRUE);
 			break;
 		case OP_RCONV_TO_U4:

mono/mini/mini-arm64.c

@@ -4304,6 +4304,7 @@ mono_arch_output_basic_block (MonoCompile *cfg, MonoBasicBlock *bb)
 			arm_fcvtzu_sx (code, dreg, sreg1);
 			break;
 		case OP_RCONV_TO_I8:
+		case OP_RCONV_TO_I:
 			arm_fcvtzs_sx (code, dreg, sreg1);
 			break;
 		case OP_RCONV_TO_U8: