feat: Add ifelse test for armv8m

[dop-amin]

Adds a test to cover #236. No fix needed @mkannwischer?

Output of the test:

.equ RCxy_44, 14
.macro shift x, y
.if (RCxy_\x\()\y % 2) == 0
    vshr.u32 SHR_l, A_l, #32-(RCxy_\x\()\y/2)
.else
    vshr.u32 SHR_h, A_l, #32-((RCxy_\x\()\y-1)/2)
.endif
.endm

        start:
                                           // Instructions:    1
                                           // Expected cycles: 1
                                           // Expected IPC:    1.00
                                           //
                                           // Wall time:     0.02s
                                           // User time:     0.02s
                                           //
                                           // ----- cycle (expected) ------>
                                           // 0                        25
                                           // |------------------------|----
        vshr.u32 q4, q1, #32-(14/2)        // *.............................

                                                // ------ cycle (expected) ------>
                                                // 0                        25
                                                // |------------------------|-----
        // vshr.u32 SHR_l, A_l, #32-(14/2)      // *..............................

        end:

[dop-amin]

• Make test fail if other branch would be chosen, i.e., put something not parsable into the "impossible" branch.